More than four decades later, this remains the deadliest accident in aviation history, claiming 583 lives, injuring dozens, and leaving thousands with lifelong psychological trauma.
After a few hours of delays, passengers aboard Pan Am Flight 1736 were finally ready for takeoff. In just a few minutes, they would embark on their much-anticipated journey over the Mediterranean Sea.
The Pan Am aircraft was slowly taxiing down the single runway at Tenerife airport when passengers suddenly noticed the plane veering to the left. What seemed like a simple deviation from the path turned out to be a desperate attempt by Captain Victor Grubbs and First Officer Robert Bragg to navigate the aircraft.
They were met with a horrifying sight. A KLM 747 was barreling down the runway toward them. Captain Grubbs and the crew did everything possible to avoid a collision, even veering onto the grass.
But it was too late.
On March 27, 1977, at 5:06 PM local time, Pan Am Flight 1736 collided violently with KLM Flight 4805 on the runway of Los Rodeos Airport in the Canary Islands.
An image taken just before the accident shows Pan Am Flight 1736 parked directly behind KLM Flight 4805. (Photo: HistoryNet).
How could the collision between two seemingly rare 747s happen?
In the years that followed, public opinion largely blamed KLM Captain Jacob van Zanten. However, a series of mistakes and astonishing coincidences led to this disaster.
Initially, neither aircraft was scheduled to arrive at Tenerife, let alone on the same runway at the same time. Both were transporting passengers to vacation on Grand Canary Island. However, before the two 747s could land, a terrorist group bombed the Las Palmas airport terminal on Grand Canary. As a result, all flights to the island were delayed and rerouted to nearby Tenerife.
To pass the time, Captain Grubbs invited 380 passengers aboard the Pan Am to visit the cockpit of the 747. According to a recording recovered after the accident, Grubbs was confused about why they had to land when the plane still had plenty of fuel. This was also seen as a coincidence, as if Pan Am had continued flying, the accident might have been avoided.
Meanwhile, the 234 passengers aboard the KLM disembarked the aircraft and entered the Tenerife terminal. Captain Van Zanten decided to refuel the plane. Ironically, just as he started refueling, the airport resumed operations. The KLM sat idle, while the Pan Am was parked right behind the KLM. Due to its large size, it could not overtake to take off first.
At this point, the KLM was heavier due to the additional fuel and required a longer runway to take off. The disaster was only minutes away.
Meanwhile, fog began to thicken, rapidly reducing visibility.
Before 5 PM, the control tower allowed KLM to start its engines and enter the runway. Due to a technical communication error between the crews and the control tower, the Pan Am missed its exit, while the KLM executed a 180-degree turn onto the same runway where the Pan Am was taxiing. Additionally, this airport had no ground radar.
“Prepare for takeoff. I will call you”, the control tower’s voice became the most misunderstood phrase in aviation history. Captain Van Zanten only heard the word “takeoff”. As the KLM accelerated, First Officer Schreuder asked, “Is Pan Am still on the runway?” but Van Zanten did not hear these crucial last moments.
The horror unfolded as the Pan Am aircraft suddenly emerged from the fog. Van Zanten desperately attempted to lift the aircraft into the air but failed. The tail of the plane scraped a deep 20-meter trench on the runway. The collision resulted in the deaths of all passengers on KLM Flight 4805 and most aboard Pan Am Flight 1736.
Debris from Pan Am Flight 1736 scattered across the Los Rodeos runway. (Photo: PA/Getty Images).
The scene outside the aircraft was chaotic, with flames roaring and enormous plumes of black smoke rising from the Pan Am plane. The wreckage of KLM Flight 4805 was engulfed in flames 365 meters from the runway. Despite their own injuries, the crew of Pan Am and the four surviving cockpit members did everything possible to guide the remaining passengers to safety.
In the years following the Tenerife accident, the island’s government completed a new airport equipped with ground radar. Additionally, since the Tenerife disaster, international aviation has forever changed to prevent another similar catastrophe.
